As device nodes shrink below 10 nanometers (nm) in advanced semiconductor manufacturing, new materials are introduced for better device performance and manufacturability. Examples of new materials being considered include cobalt via contacts, aluminum nitride etch stop layers, and titanium nitride barrier layers.
Titanium nitride has various applications in the semiconductor industry, such as hard masks, metal barriers, conductive electrodes, metal gates, and many others. Titanium nitride has good metal diffusion blocking characteristics which is desirable for a barrier material and also has a low resistivity of about 30-70 micro Ohm-cm after annealing. Titanium nitride films can be made by physical vapor deposition and chemical vapor deposition processes.
Post etch cleaning chemistry that is compatible with cobalt, aluminum nitride, and titanium nitride barrier materials enables manufacturing processes at the smaller and more advanced nodes. In the back end of line (BEOL), copper (Cu) is still used as an interconnect metal line, so a cleaning chemistry formulation that is compatible with copper as well as the new materials is advantageous. There is a continuing need for cleaning compositions with controlled etch rate and selectivity for titanium nitride hard mask materials over other films in the device which can include cobalt, copper, aluminum nitride, low-k dielectrics, and titanium nitride barrier materials.